Problem: $\overline{AC}$ is $4$ units long $\overline{BC}$ is $8$ units long $\overline{AB}$ is $4\sqrt{5}$ units long What is $\cos(\angle ABC)$ ? A C B 4 8 4\sqrt{5}
Answer: SOH CAH TOA os = djacent over ypotenuse adjacent $= \overline{BC} = 8$ hypotenuse $= \overline{AB} = 4\sqrt{5}$ $\cos(\angle ABC )=\frac{8}{4\sqrt{5}}$ $=\dfrac{2\sqrt{5} }{5}$